Frosty 502 DX of Formatic, Replot, Finland. It was bought by Kässbohrer in 2008. Here is the Frosty, created in 1982, which can move with or without a driven tracked trailer. http://spevemat.fr/categorie-produit/vehicules/, https://www.pistenbully.com/uploads/tx_z7simpledownloads/K-Info_spezial_FR_10.11.09_DL.pdf, http://www.agriaffaires.com/occasion/tracteur-autre/13681826/chenillette-formatic-652dx-diesel-932hr-remorque.html, www.formatic-by-k.com, https://www.youtube.com/watch?v=2VoWP8n7Sds, https://www.youtube.com/watch?v=Wtznxucc2ZM